High yield production of levulinic acid by catalytic partial oxidation of cellulose in aqueous media

Abstract

A high yield of levulinic acid was produced by directly converting cellulose over a ZrO 2 catalyst by a one-pot catalytic aqueous phase partial oxidation (APPO) process. Compared to conventional acid hydrolysis, APPO is a highly selective and environmentally benign process with merits of easy recovery and re-use of heterogeneous catalysts.Conversion of cellulosic biomass is of vital importance in the biofuel/ biochemical industry. 1 Recently, several groups have reported that combining hydrolysis and hydrogenolysis of cellulose over noble metal 2 or metal carbide 3 catalysts produced sugar alcohols or polyols such as sorbitol, mannitol, or ethylene glycol, which are precursors in the production of fuels, polymers, and pharmaceuticals. However, these processes suffer from the high costs associated with mineral acids, cellulase enzymes, noble metals, external hydrogen, etc.

Catalytic Conversion of Lignocellulosic Biomass to Value-Added Organic Acids in Aqueous Media

“…Our group recently presents an alternative pathway, aqueous phase partial oxidation (APPO), to produce levulinic acid directly from cellulose with lean air and water over inexpensive solid metal oxide catalysts [85]. The maximum obtainable yield of levulinic acid in the APPO process is *60 mol%, comparable to the yields of levulinic acid which have been achieved via acid hydrolysis.…”

“…Hydrolysis of carbohydrate biomass followed by sugar degradation can produce organic acids by an acid-catalyzed hydrolysis reaction [96]. Recently, our group has demonstrated that aqueous phase partial oxidation is an alternative pathway that directly converts cellulose to carboxylic acids [85].…”

Zeolite Catalyzed Transformation of Carbohydrates to Alkyl Levulinates

“…Y-and Beta-type zeolites gave 10-40 % yield of levulinic acid from glucose/fructose/cellulose in water at temperatures between 110-240 8C. [11] Despite the many advantages of zeolites, they are not hydrothermally stable in water during the reaction, which leads to a loss of structural integrity and can, therefore, not be recycled. Alternatively, Schraufnagel and Rase have reported that sucrose can be transformed into levulinic acid in water using acidic ion-exchange resins as catalysts at temperatures between 100 and 140 8C.…”

Catalytic Oxidation Pathways for the Production of Carboxylic Acids from Biomass

“…Levulinic acid derived from cellulose is considered a suitable building block for synthesizing hydrocarbon liquid fuels or valeric esters as fuel additives, as well as a variety of chemicals [ 151 ]. Typically, equivalent molar amounts of levulinic acid ( 2 ), D -threo-hexo-2,5-diulose ( 3 ), 2,5-diketogluconic acid (4 ), 2-hydroxy-3-butanedioic acid ( 5 ), and glycolic acid ( 6 ) (Reprinted from ref.…”

“…[ 138 ], Copyright 1997, with permission from Elsevier) and formic acid can be generated in the acid-catalyzed conversion of cellulose without oxygen participation in the overall reactions [ 152 ]. Recently, Lin's group developed a nontraditional pathway, aqueous-phase partial oxidation (APPO), for the direct conversion of cellulose into levulinic acid with air and water in the presence of ZrO 2 catalyst [ 151 ]. The maximum yield of levulinic acid in the APPO Fig.…”